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UID:20150303T173621EST-3010XKUrfZ@http://molbio.princeton.edu/
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DESCRIPTION:MolBio Seminar Series\nSpeaker\nBruce R. Levin\n\n\nEmory Unive
rsity\n\n\n&nbsp\;\n&nbsp\;\n&nbsp\;\n&nbsp\;\n&nbsp\;\n&nbsp\;\n\n\nSemin
ar Topic\nThe Population and Evolutionary Dynamics of Adaptive Immunity in
Bacteria:&nbsp\; CRISPR and CAS are Not Just the Tools of Capitalist Mole
cular Biologists.\nArguable\, surely to those who work on it\, the demonst
ration that the Clustered Regularly Interspaced Short Palindromic Repeats
(CRISPR) regions and their associated sequences (Cas) that abound in the g
enomes of the majority of Archaea and nearly half the Bacteria can serve a
s an adaptive immune system has been the single most important new finding
in Microbiology and Molecular Biology this millennium.&nbsp\;&nbsp\; By i
ncorporating 30 or so base pairs of the infecting DNA into regions between
these palindromic repeats\, when subsequently infected by DNA with sequen
ces identical to that of the incorporated “spacers”\, through a process me
diated by small RNAs\, CRISP-Cas encoding bacteria and archaea abort the i
nfection.&nbsp\;&nbsp\; When these infectious DNAs are those of necessaril
y lethal (lytic) bacterial viruses the advantages of CRISPR-Cas mediated i
mmunity are straightforward and easily demonstrated experimentally as well
as theoretical\, albeit more kinky than anticipated. &nbsp\;But not all i
nfectious DNAs are deleterious\; some like plasmids and temperate bacterio
phages may bear genes\, such as those conferring resistance that in the pr
esence of antibiotics that can be very much to the advantage of recipient
bacteria. &nbsp\;In this talk I will present the results of the mathematic
al and computer simulation modeling and population and evolutionary dynami
c and experiments we have been doing to explore the upside of CRISPR-Cas i
mmunity\, protection against infections against lethal infections with lyt
ic and temperate phage\, and the downside of this immune system\, preventi
ng the acquisition of plasmids and temperate phage bearing beneficial gene
s.&nbsp\;&nbsp\; I will consider the nature of and factors limiting the CR
ISPR-Cas mediated Lamarckian - Darwinian arms races between bacteria and p
hage\, and present a hypothesis to account for the extraordinary diversity
in the existence\, number and function of CRISPR-Cas systems within and b
etween species of bacteria and archaea.\n&nbsp\;\nResearch Lab\n&nbsp\;htt
p://www.eclf.net/\n&nbsp\;\nAudience\nFree and open to the university comm
unity and the public
DTSTART:20140328T120000
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LOCATION:Lewis Thomas Lab\, 003 (Washington Road \, Princeton)
SUMMARY:Bruce R. Levin (Emory University)
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